SANTA CRUZ -- For Santa Cruz County residents, 2012 was an extraordinary year for innovation.

The county ranked fifth in the nation with 4.2 patents per 1,000 employees, behind Santa Clara County, Corvallis, Ore., Boulder, Colo., and Rochester, Minn., according to the Brookings Institution, which released a report Friday on the role of patenting on prosperity in the United States.

In fact, the county moved up from eighth in the nation, based on 1,204 patents granted to residents from 2007 through 2011, averaging 3.2 patents per 1,000 employees.

What is driving all this innovation?

PLANTRONICS PATENTS

Santa Cruz is home to Plantronics, an innovative headset maker and the largest private employer with more than 500 workers locally. Plantronics has been granted more than 100 patents in the past eight years, compared to 48 from 1976 to 2003.

Several patents have to do with sensors Plantronics was the first to integrate into headsets "that provide the users new capabilities depending on whether or not they have the headset on or off," said Genevieve Haldeman, Plantronics' vice president of global communications. "We call this contextual intelligence."

Among the multiple patent-holders is Christophe Koch, listed as an inventor or co-inventor of five headsets and a charger.

As employees work in teams, often there are multiple inventors living in different locations for a single patent.

"We allocated a patent to a metro area if even one of its inventors lived there," said Jonathan Rockwell, lead author of the Brookings report. "We tried the other way, assigning only the fraction of the patent invented by people in the metro area and got similar results and rankings, so we went with the first, since it strikes us as more intuitive."

Santa Cruz also is home to UC Santa Cruz, which has highly trained faculty who land federal grants for research.

From 2007 to 2011, 32 patents were issued to UCSC, according to UCSC's Office for Management of Intellectual Property.

A third, and probably the largest, source of innovation is people who live in Santa Cruz County and commute to jobs outside the county.

In 2011, the top patenting companies for Santa Cruz County inventors, according to Brookings, were:

Apple Computer, Cupertino, 64 patents;

Applied Materials, Santa Clara, 34;

Tela Innovations, Campbell, 25;

Oracle America, Redwood Shores, 17;

Seagate Technology, Cupertino, 16;

Adobe Systems, San Jose, 15.

PATENT PRODUCTIVITY

Brookings found patents are associated with growth in gross domestic product per worker, $100,557 in Santa Cruz County in 2011, ranking 47th out of 358 metro areas, though tech employed only 3.8 percent of the workers, ranking 88th.

Rockwell pointed out that patent claims, in which the inventor or inventors explain what the invention is and what it can do, are valuable because they are associated with productivity.

The patent from a Santa Cruz County inventor with the most claims, 108, of all patents granted in 2011 was a rapid iris acquisition, tracking and imaging system granted to AOptix in Campbell.

The inventors were Malcolm J. Northcott from Felton and J. Elon Graves from Los Gatos.

Other patents with 100 or more claims that year were granted to Applied Materials, with Santa Cruz resident Robin Tiner among the inventors; TiVo, with Felton resident Paul Stevens among the inventors; and the University of California, with electrical engineering professor Holger Schmidt among the inventors.

Downtown Santa Cruz is attracting more inventors.

Philippe Kahn, inventor of the camera phone with dozens of patents to his name, founded Fullpower Technologies in 2003 and had 75 people working downtown as of September. Last month, he announced several new patents for technologies for wearable noninvasive medical devices that he envisions delivering personalized doses of medicine and revolutionizing health care.

Other inventors have found friendly environs at Cruzioworks downtown.

Chris Yonge, co-founder of Makers Factory, has six patents. Glenn Stearns of Stearns & More Capital holds three patents in artificial intelligence and software agents. And Tom Padula of Humble Earth Productions has a patent pending on his manmade fireflies.

Oystein Saebo, who co-founded Isentio in Norway, has a patent for identifying multiple bacteria directly from a patient sample using DNA sequencing technology. The company now has an office in Sunnyvale, and Saebo and his family live in Santa Cruz.